1. Field
Embodiments relate to the field of substrate processing using ions. More particularly, the present embodiments relate to a system and structure for providing an ion beam to a substrate.
2. Discussion of Related Art
Present day plasma based processing systems include apparatus in which a substrate is held stationary while immersed in a plasma that encompasses the substrate, as well as apparatus that employ scanning of a substrate in a process chamber adjacent to a plasma chamber or plasma source. The latter type of apparatus facilitates the use of relatively compact ion or plasma sources, since only a portion of a substrate need be exposed to ions from a plasma at a given time. For example, some configurations employ plasma chambers in which a rectangular extraction assembly is used to extract an ion beam having an elongated cross section.
To expose an entire substrate to ions from the plasma source, the substrate is scanned adjacent to the extraction assembly along a given direction. At any instance, a portion of the substrate defined by the size and shape of the extraction assembly is exposed to an ion beam having an elongated cross section, which may be as wide as the substrate being processed, wider or narrower. An advantage of this approach is that the exposed portion need only be as narrow as a few centimeters or even millimeters along the direction in which the substrate is scanned. In this manner, a plasma (ion) source may be employed that has dimensions smaller than the substrate being exposed, at least along one direction, which may allow large substrates to be treated without having to employ a plasma source that matches or exceeds the substrate size.
However, in such plasma systems, a process chamber may be significantly larger than the plasma source chamber in order to accommodate substrate scanning. This imposes a burden upon various components of a plasma processing system including process chamber housing components, scanning drives, pumps, and other components. As substrates scale to larger sizes, the concomitant scaling of some or all these components is contemplated. This places a further burden on plasma processing equipment manufacturers, as well as tool users, such as semiconductor manufacturers, solar cell manufacturers, and other device manufacturers that may employ such systems.